Photo-luminescent behavior and computational studies of cool green light emanating terbium (III) complexes with heterocyclic sensitizers

A series of terbium complexes were synthesized using the liquid-assisted grinding method. FTIR (Fourier-transform infrared) and NMR (nuclear magnetic resonance) spectroscopy aided in the elucidation of bonding and structure. Thermal, PXRD (powdered X-ray diffraction), SEM (scanning electron microscopic) and EDAX (electron dispersive X-ray spectra) analysis of the complexes were carried out. Luminescent properties study of complexes in solid and solution displayed efficacious green emission because of the most intense ⁵D₄ → ⁷F₅ peak, observed at 549 nm for solid and 545 nm for solution state. Judd-Ofelt study of the complexes were done with the assistance of NIR (near Infrared) absorption spectra. Lasing properties analysis indicated their application in laser devices. Reflectance spectra of complexes was utilized for the evaluation of band gap and Urbach energy, moreover band gap was also evaluated through DFT (density function theory) calculations, the obtained parameters suggested the possibility of using these complexes as semiconductors in various devices. Further biological studies show antioxidant and antimicrobial behavior of the complexes which was further confirmed by the molecular docking.